RU2788630C1 - Terminal and transmission method - Google Patents

Abstract

FIELD: wireless communication.

SUBSTANCE: control unit in a terminal uses channel quality as a base for selection of either the first method for transmission of a random access signal including a preamble section and a data section or the second method for transmission of a random access signal, which includes a preamble section and does not include a data section. A transmission unit transmits the random access signal based on the selected method.

EFFECT: improvement of the efficiency of processing of random access.

28 cl, 12 dwg

Description

Technical field

[0001] The present invention relates to a terminal and a transmission method.

State of the art

[0002] The 3rd Generation Partnership Project (3GPP) consortium has completed the specification for Edition 15 of the New Radio (NR) radio access technology for implementing 5G mobile communication systems. NR supports features for realizing Ultra Reliable and Low Latency Communication (URLC) combined with high speed and high bandwidth, which are the basic requirements for an enhanced mobile broadband network (Mobile Broadband, eMBB) (see. for example, non-patent literature (hereinafter referred to as "NPL" (Non-Patent Literature)) 1-7).

Link List

Non-Patent Literature

[0003]

NPL 1

3GPP TS 38.211 V15.4.0, “NR; Physical channels and modulation (Release 15)", December 2018;

NPL 2

3GPP TS 38.212 V15.4.0, “NR; Multiplexing and channel coding (Release 15)", December 2018;

NPL 3

3GPP TS 38.213 V15.4.0, “NR; Physical layer procedure for control (Release 15)", December 2018;

NPL 4

3GPP TS 38.214 V15.4.0, “NR; Physical layer procedures for data (Release 15)”, December 2018

NPL 5

3GPP TS 38.300 V15.4.0, “NR; NR and NG-RAN overall description; Stage 2 (Release 15)", December 2018

NPL 6

3GPP TS 38.321 V15.4.0, “NR; Medium access control (MAC) protocol specification (Release 15)”, December 2018

NPL 7

3GPP TS 38.331 V15.4.0, “NR; Radio resource control (RRC) protocol specification (Release 15)”, December 2018

NPL 8

B. Bertenyi, S. Nagata, H. Kooropaty, X. Zhou, W. Chen, Y. Kim, X. Dai, and X. Xu, "5G NR radio interface", Journal of ICT, Vol. 6 and 2, pp. 31-58, 2018.

NPL 9

RP-182881, "New work item: 2-step RACH for NR", ZTE Corporation, Sanechips, December 2018

Disclosure of the essence of the invention

[0004] However, random access processing has not been comprehensively studied.

[0005] One non-limiting and exemplary embodiment of the present invention facilitates the provision of a terminal and transmission method that can improve random access processing performance.

[0006] A terminal according to an embodiment of the present invention includes: a control circuit configured to select one of a first method and a second method based on channel quality, the first method is for transmitting a random access signal including a preamble section and a data section , the second method is for transmitting a random access signal including a preamble section but not including a data section; and a transmission circuit configured to transmit the random access signal based on the selected method.

[0007] It should be noted that these general or specific aspects may be achieved by a system, device, method, integrated circuit, computer program, or recording medium, as well as by any combination of system, device, method, integrated circuit, computer program, and recording media.

[0008] According to an exemplary embodiment of the present invention, the efficiency of random access processing can be improved.

[0009] Additional benefits and advantages of the disclosed exemplary embodiments will become apparent from the description of the invention and the drawings. Benefits and/or advantages may be separately obtained using the various embodiments and features presented in the description and drawings, which need not be provided all in order to obtain one or more of such benefits and/or advantages.

Brief description of the drawings

[0010]

in FIG. 1 shows an example of a 4-way random access procedure;

in FIG. 2 shows an example of a 2-stage random access procedure;

in FIG. 3 is a block diagram illustrating a configuration example of a terminal part according to Embodiment 1;

in FIG. 4 is a block diagram illustrating a configuration example of a base station according to Embodiment 1;

in FIG. 5 is a block diagram illustrating a configuration example of a terminal according to Embodiment 1;

in FIG. 6 shows an example of a random access procedure according to Embodiment 1;

in FIG. 7 is a flowchart illustrating an operation example of a base station according to Embodiment 1;

in FIG. 8 is a flowchart illustrating an operation example of a base station according to Embodiment 1;

in FIG. 9 shows an example of a random access procedure according to Embodiment 2;

in FIG. 10 shows an example of a random access procedure according to Embodiment 4;

in FIG. 11 shows an example configuration of message A time division multiplexed;

in FIG. 12 shows an example configuration of message A frequency division multiplexed.

Implementation of the invention

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0012]

[Random access procedure]

In NR Release 15, a terminal (also referred to as a "mobile station" or "User Equipment" (User Equipment, UE)) transmits a random access signal (also referred to as a "Random Access Channel" (RACH) or "Physical RACH" (Physical RACH, PRACH) base station (also called "gNB" or "eNB"), for example, in the following cases:

(1) During initial access (eg, transition from the RRC_IDLE state to the RRC_CONNECTED state).

(2) When returning from the RRC_INACTIVE state to the RRC_CONNECTED state.

(3) When generating downlink or uplink data during a connection (eg, in the uplink synchronization state of "out of synchronization" in the RRC_CONNECTED state).

(4) When requesting system information (System Information, SI) on demand.

(5) When recovering from beam loss (Beam failure recovery, BFR)).

[0013] By transmitting a random access channel signal, an attempt is made to connect or recover synchronization by the terminal with the base station. The sequence of operations performed for such a connection or recovery of synchronization by the terminal with the base station is called the "random access procedure".

[0014] In NR Edition 15, the random access procedure consists of, for example, the four steps shown in FIG. 1 (referred to as "4-way random access procedure" or "4-way RACH procedure") (see, for example, NPL 8).

[0015] <Step 1: transmit message 1>

The terminal (e.g., UE) randomly selects for actual use a PRACH preamble resource from a set of potentially usable resources (e.g., resources indicated by a combination of time resources, frequency resources, and sequence resources) for a preamble signal (hereinafter referred to as "RACH preamble", "PRACH preamble or simply "preamble"). The terminal then transmits the PRACH preamble to the base station (eg, gNB) using the selected PRACH preamble resource. The PRACH preamble may be referred to as "message 1", for example.

[0016] <Step 2: message transmission 2>

Upon detection of a PRACH preamble, the base station transmits a RACH response (also referred to as a "Random Access Response" (RAR)). The RAR may be referred to as "message 2", for example. It should be noted that at this point, the base station cannot identify the terminal that transmitted the PRACH preamble. Thus, RAR is transmitted, for example, in the entire cell covered by the base station.

[0017] The RAR includes, for example, information about the resource (uplink resource) used by the terminal for transmitting the uplink signal (step 3: transmitting message 3) or transmission timing information for transmitting the uplink by the terminal. Meanwhile, when the terminal that transmitted the PRACH preamble does not receive RAR within a predetermined period (for example, called the RAR receive window) starting from the transmission timing of the PRACH preamble, the terminal again selects the PRACH preamble resource and transmits the PRACH preamble (in other words, retransmits the message 1).

[0018] <Step 3: Send Message 3>

The terminal transmits a "message 3" including, for example, a Radio Resource Control (RRC) connection request, a scheduling request, and the like, using an uplink resource indicated by the base station via RAR.

[0019] <Step 4: message transmission 4>

The base station sends a message (referred to as "message 4") to the terminal including identification information (eg, UE ID) to identify the terminal. The base station transmits message 4 to confirm that there is no contention between the plurality of terminals (collision resolution). It should be noted that, for example, a Cell-Radio Network Temporary Identifier (C-RNTI), a temporary C-RNTI, etc. can be used as a UE identifier.

[0020] One example of a 4-stage random access procedure has been described above.

[0021] With regard to NR Edition 16, in order to efficiently connect or re-establish synchronization between a terminal and a base station with low latency, a two-stage random access procedure, such as those shown in FIG. 2 (which may also be referred to as "2-way random access" or "2-way RACH") (see, for example, NPL 9).

[0022] <Step 1: Message A transmission>

The terminal transmits to the base station a message (hereinafter referred to as “message A”) including information corresponding to message 1 (in other words, preamble) and message 3 corresponding to step 1 and step 3 of the 4-way random access procedure (see, for example, FIG. 1).

[0023] <Step 2: transmission of message B>

When message A is detected, the base station transmits message B. Message B includes, for example, information corresponding to message 2 or message 4 of the 4-way random access procedure (see, for example, FIG. 1) (for example, information of one or both messages 2 and 4).

[0024]

[Transmission power control in random access procedure]

In the 4-round random access procedure in NR, message 1 and message 3 perform Transmit Power Control (TPC). For example, the PPRACH transmit power for the PRACH preamble carried in message 1 is obtained according to the following Equation 1 (see, for example, NPL 3):

[0025] Here, PCMAX indicates the maximum transmit power at which the terminal can transmit, PPRACH_target indicates the target received power value for the PRACH preamble (eg, a parameter configured by the base station), and PL indicates the bandwidth loss level measured by the terminal.

[0026] In addition, the transmission power of the PPUSCH of the data signal (e.g., uplink data channel (e.g., Physical Uplink Shared Channel, PUSCH)) transmitted in message 3 is obtained according to, for example, with the following equation 2 (see, for example, NPL 3):

[0027] Here, P _CMAX indicates the maximum transmit power at which the terminal can transmit, P _{O_PUSCH} indicates an offset value (a parameter configured by the base station) for the target received power value P _{PRACH_target} for the PRACH preamble, given by, for example, equal to 3. The symbol "μ ' indicates a parameter representing the Subcarrier Spacing (SCS) of the PUSCH used to transmit message 3. For example, µ = 0 when the subcarrier spacing is 15 kHz and µ = 1 when the subcarrier spacing is 30 kHz (see, for example, NPL 1). The symbol "PL" indicates the bandwidth loss level measured by the terminal, "α" indicates a weighting factor representing the degree of compensation for the bandwidth loss (eg, a parameter configured by the base station). The symbol "Δ _TF " indicates a parameter specified by the Modulation and Coding Scheme (MCS) and the like of the PUSCH. The symbol "f" is a value considering the accumulated values, including the TPC command in the feedback control and the power ramp in the past.

[0028] The TPC command for PUSCH sent in message 3 is included, for example, in the RAR sent in message 2.

[0029] In the 2-round random access procedure, the terminal transmits in message A the signal (eg, PRACH preamble) corresponding to message 1 and the signal (eg, PUSCH) corresponding to message 3 in the 4-round random access procedure with similar timings (or while synchronizing). Accordingly, in message A, the terminal transmits message A (eg, PUSCH signal) without indication (eg, TPC command included in RAR) from the base station.

[0030] For example, in a 2-way random access procedure, open loop control is expected to be applied to the TPC for each PRACH and PUSCH preamble in message A. For example, the terminal calculates the transmit power for the PRACH preamble based on Equation 1 in the same manner as, for example, , in a 4-way random access procedure. At the same time, with respect to PUSCH, a possible way for the terminal is to remove the TPC command section (for example, "f" in Equation 2) related to the feedback control in Equation 2, or configure the TPC command section according to the given offset value.

[0031] However, in such a method, transmission power control in the PUSCH is not performed by the base station. Thus, the transmission quality of message A (eg, PUSCH) may be degraded.

[0032] In addition, in the 2-round random access procedure for the PRACH preamble, for example, orthogonal or quasi-orthogonal resources are used. However, when the orthogonal resources are also used for the PUSCH according to the orthogonal resources for the PRACH, more radio resources will be reserved for the PUSCH, and therefore the resource utilization efficiency deteriorates. Accordingly, for example, a method is expected in which a PUSCH resource is allocated according to orthogonal resources for a plurality of PRACH preambles. With these resources, signal collision between terminals in a 2-way random access procedure is more likely to occur in PUSCH resources than in PRACH preamble resources.

[0033] If a terminal for which the transmission quality of the PUSCH does not satisfy the given reliability transmits the PUSCH in message A, it is likely to result in a PUSCH collision. Thus, interference to other terminals in PUSCH resources is likely to increase. In such a case, it is desirable for the terminal to transmit the PRACH preamble in message A without transmitting the PUSCH, ie, reverting from the 2-way random access procedure to the 4-way random access procedure.

[0034] However, the transmission power control considering the return operation in the 2-stage random access procedure has not been comprehensively investigated.

[0035] Therefore, in an exemplary embodiment of the present invention, a method for controlling uplink transmission power in a 2-stage random access procedure will be described.

[0036] Hereinafter, embodiments of the present invention will be described in detail.

[0037] (Embodiment 1)

[Brief description of the communication system]

The communication system in accordance with each embodiment of the present invention includes a base station 100 and a terminal 200.

[0038] FIG. 3 is a block diagram illustrating a configuration example of a portion of a terminal 200 according to each embodiment of the present invention. In terminal 200 shown in FIG. 3, the controller 209 (corresponding to the control scheme) selects one of the first method based on the channel quality for transmitting a random access signal (eg, message A) including a preamble section (eg, PRACH preamble) and a data section (eg, PUSCH), and a second method for transmitting a random access signal including a preamble section but not including a data section. The transmitter 217 transmits the random access signal based on the selected method.

[0039]

[Base Station Configuration]

FIG. 4 is a block diagram illustrating a configuration example of a base station 100 according to Embodiment 1 of the present invention. FIG. 4, the base station 100 includes a controller 101, a data generator 102, an encoder 103, a modulator 104, a senior control signal generator 105, an encoder 106, a modulator 107, a downlink control signal generator 108, an encoder 109, a modulator 110, a signal distributor 111, an inverse fast Fourier Transform (IFFT) section 112, a transmitter 113, an antenna 114, a receiver 115, a Fast Fourier Transform (FFT) section 116, an extractor 117, a detector 118, a demodulator 119, and a decoder 120.

[0040] The controller 101 determines the information for transmitting message A by the terminal 200 (also referred to as the "message A transmission parameter"), and outputs certain information to the extractor 117, demodulator 119, and decoder 120. In addition, the controller 101 outputs certain information to the high signal generator 105 management.

[0041] The information for transmitting message A includes, for example, transmission power control information on the PRACH preamble (eg, preamble section) and PUSCH (eg, data section) of message A. The information for transmitting message A may also include information about PRACH preamble resources, PUSCH resources, PUSCH Transport Block Size (TBS), or MCS of message A. Also, for example, when terminal 200 transmits message A containing Uplink Control Information (UCI), the information for message transmission, A may include UCI transmission information.

[0042] In addition, the controller 101 determines the allocation of radio resources (for example, downlink resources, MCS, etc.) for the downlink signal to transmit a data signal (for example, message B, etc.), a control signal over high level (eg, senior control signal) or downlink control information (eg, downlink control signal). The controller 101 outputs certain information to encoders 103, 106, and 109, modulators 104, 107, and 110, and signal distributor 111. In addition, the controller 101 outputs certain information to the downlink control signal generator 108 .

[0043] In addition, based on the decoding result of message A (e.g., control plane data (C-Plane) or user plane data (User Plane, UP)) input from decoder 120, and the detection result of message A (e.g., PRACH preamble ) input from the detector 118, the controller 101 determines the information to be included in the message B, and outputs the determined information to the data generator 102.

[0044] The data generator 102 generates an information bit sequence (in other words, downlink data) of the message B using information to be included in the message B input from the controller 101, and outputs the generated information bit sequence to the encoder 103.

[0045] The encoder 103 performs error correction encoding on the sequence of information bits (data signal) inputted from the data generator 102 and outputs the coded data signal to the modulator 104.

[0046] The modulator 104 modulates the data signal inputted from the encoder 103 and outputs the modulated data signal to the signal distributor 111 .

[0047] The high control signal generator 105 generates a control information bit sequence (high control signal) using the control information input from the controller 101, and outputs the generated control information bit sequence (high control signal) to the encoder 106.

[0048] The encoder 106 applies error correction coding to the control information bit sequence inputted from the high control signal generator 105 and outputs the encoded control signal to the modulator 107.

[0049] The modulator 107 modulates the control signal inputted from the encoder 106 and outputs the modulated control signal to the signal distributor 111 .

[0050] The downlink control signal generator 108 generates a control information bit sequence (downlink control signal) using the control information input from the controller 101, and outputs the generated control information bit sequence to the encoder 109. Accordingly, the downlink control information generator 108 link may scramble control information (eg, Physical Downlink Control Channel (PDCCH)) for terminals using identification information (eg, Random Access-RNTI (RA-RNTI)) for all terminals , UE-specific identification information (e.g., C-RNTI), etc.

[0051] The encoder 109 applies error correction coding to the control information bit sequence input from the downlink control signal generator 108 and outputs the encoded control signal to the modulator 110.

[0052] The modulator 110 modulates the control signal inputted from the encoder 109 and outputs the modulated control signal to the signal distributor 111.

[0053] Based on the information indicating the radio resources inputted from the controller 101, the signal distributor 111 maps the data signal inputted from the modulator 104, the senior control signal inputted from the modulator 107, or the downlink control signal inputted from the modulator 110 to the radio resources. The signal 111 outputs to the IFFT section 112 the downlink signal to which the signal is mapped.

[0054] The IFFT section 112 performs transmission waveform generation processing such as Orthogonal Frequency Division Multiplexing (OFDM) on the signal input from the signal distributor 111 . In the case of OFDM transmission with the addition of a cyclic prefix (Cyclic Prefix, CP), IFFT section 112 adds a CP (not shown). The IFFT section 112 outputs the generated waveform to the transmitter 113.

[0055] The transmitter 113 performs radio frequency (Radio Frequency, RF) processing, such as digital-to-analog (Digital-to-Analog, D/A) conversion, up-conversion, etc., on the signal input from section 112 IFFT, and transmits a radio signal to terminal 200 via antenna 114.

[0056] Receiver 115 performs RF processing such as downconversion or analog-to-digital (A/D) conversion on the uplink waveform received from terminal 200 via antenna 114, and after processing receive outputs the uplink waveform to the FFT section 116 .

[0057] The FFT section 116 performs, on the uplink waveform input from the receiver 115, FFT processing to convert the time domain signal into a frequency domain signal. The FFT section 116 outputs the frequency domain signal obtained by the FFT processing to the extractor 117.

[0058] Based on the information inputted from the controller 101, the extractor 117 extracts from the signal inputted from the FFT section 116, a radio resource portion by which the PRACH preamble is transmitted, a radio resource portion by which UCI is transmitted, or a radio resource portion by which PUSCH messages are transmitted A. The allocator 117 outputs to the detector 118 the allocated radio resource portion through which the PRACH preamble is transmitted, and outputs to the demodulator 119 the allocated radio resource portion through which the UCI is transmitted or the allocated radio resource portion through which the PUSCH message A is transmitted.

[0059] The detector 118 performs detection of the PRACH preamble on the part of the radio resource inputted from the allocator 117 that corresponds to the PRACH preamble. The detector 118 outputs the PRACH preamble detection result information to the controller 101.

[0060] Based on the information inputted from the controller 101, the demodulator 119 demodulates the radio resource part corresponding to the UCI or the radio resource part corresponding to message A data input from the allocator 117, and outputs the demodulation result (demodulation sequence) to the decoder 120.

[0061] Based on the information input from the controller 101, the decoder 120 performs error correction decoding on the demodulation result input from the demodulator 119, and outputs a decoded bit sequence (including, for example, UCI, control plane data, or UP data). For example, decoder 120 outputs the received UCI to controller 101.

[0062]

[Terminal Configuration]

FIG. 5 is a block diagram illustrating a configuration example of a terminal 200 according to an embodiment of the present invention. FIG. 5, terminal 200 includes an antenna 201, a receiver 202, an FFT section 203, an extractor 204, a demodulator 205, a decoder 206, a downlink control signal demodulator 207, a decoder 208, a controller 209, a PRACH preamble generator 210, an encoder 211, a modulator 212, an encoder 213, a modulator 214, a signal distributor 215, an IFFT section 216, and a transmitter 217.

[0063] The receiver 202 performs RF processing such as down-conversion, analog-to-digital (A/D) conversion, and the like, on the downlink waveform from the base station 100 received by the antenna 201, and outputs the received received signal (baseband signal) to the FFT section 203 . The downlink signal includes, for example, a data signal (eg, message B, etc.), a senior control signal, or a downlink control signal.

[0064] The FFT section 203 performs, on the downlink (time domain signal) waveform input from the receiver 202, FFT processing to convert the time domain signal into a frequency domain signal. The FFT section 203 outputs the frequency domain signal obtained by the FFT processing to the extractor 204.

[0065] Based on the control information (eg, radio resource information for the control signal) obtained from the controller 209, the allocator 204 extracts the data signal (eg, message B, etc.), the downlink control signal, or the senior control signal from signal inputted from section 203 FFT. The extractor 204 outputs the data signal or the senior control signal to the demodulator 205 and outputs the downlink control signal to the demodulator 207 of the downlink control signal.

[0066] The demodulator 205 demodulates the data signal or the senior control signal inputted from the extractor 204 and outputs the demodulation result to the decoder 206.

[0067] The decoder 206 performs error correction decoding using the demodulation result input from the demodulator 205 to obtain received data (eg, message B) or control information. The decoder 208 outputs the received received data or control information to the controller 209.

[0068] The downlink control signal demodulator 207 demodulates the downlink control signal inputted from the extractor 204 and outputs the demodulation result to the decoder 208.

[0069] The decoder 208 performs error correction decoding using the demodulation result input from the downlink control signal demodulator 207 to obtain control information. The decoder 208 outputs the received control information to the controller 209.

[0070] The controller 209 determines a method or parameter related to transmit power control for uplink transmission (e.g., message A transmission) based on control information input from decoder 206 or decoder 208. For example, controller 209 determines (or selects) the random access procedure to be applied (eg, 2-way random access procedure or 4-way random access procedure). In addition, the controller 209 determines the transmission parameter of the message A using information about the transmission of the message A by the terminal 200 obtained from the senior control signal input from the decoder 206. The controller 209 outputs the determined information to the PRACH preamble generator 210, the encoders 211 and 213, the modulators 212 and 214 and a signal assigner 215.

[0071] The controller 209 also outputs to the extractor 204 the radio resource information for the control signal contained in the control information input from the decoder 206 or the decoder 208.

[0072] The PRACH preamble generator 210 generates a PRACH preamble based on the control information (eg, message transmission parameter A) input from the controller 209, and outputs the generated PRACH preamble to the signal assigner 215 .

[0073] When transmitting the UCI to the base station 100, the encoder 211 performs error correction encoding on the UCI (e.g., UCI sequences) based on the information input from the controller 209, and outputs the encoded UCI (bit sequence) to the modulator 212.

[0074] Based on the information input from the controller 209, the modulator 212 modulates the UCI input from the encoder 211 and outputs the modulated UCI (modulation symbol sequence) to the signal distributor 215.

[0075] Based on the control information (e.g., message transmission parameter A) inputted from the controller 209, the encoder 213 performs error correction encoding, e.g., on a sequence of information bits (e.g., control plane data and UP data) to be transmitted in the partition message data A, and outputs the encoded bit sequence to the modulator 214.

[0076] Based on the information input from the controller 209, the modulator 214 modulates the bit sequence input from the encoder 213 and outputs a data signal (modulation symbol sequence) to the signal distributor 215 .

[0077] The signal distributor 215 maps to the radio resources specified by the controller 209 the signal input from the PRACH preamble generator 210, the signal input from the modulator 212, or the signal input from the modulator 214, and outputs to the IFFT section 216 the uplink signal to which the said signal.

[0078] The IFFT section 216 performs transmission waveform generation processing, such as orthogonal frequency division multiplexing (OFDM), on the signal input from the signal distributor 215 . In the case of OFDM transmission with CP addition, IFFT section 216 adds CP (not shown). In an alternative implementation, when the IFFT section 216 generates a single carrier waveform, a Discrete Fourier Transform (DFT) section (not shown) can be added before the signal distributor 215 . IFFT section 216 outputs the generated waveform to transmitter 217.

[0079] The transmitter 217 performs RF processing, such as D/A conversion, upconversion, and/or the like, on the signal input from the IFFT section 216, and transmits the radio signal to the base station 100 via the antenna 201.

[0080]

[Operation example of base station 100 and terminal 200]

An operation example of base station 100 and terminal 200 having the above configurations will be described.

[0081] In the present invention, during transmission of an uplink signal (e.g., message A) in a 2-way random access procedure, terminal 200 selects, for example, one of the 2-way random access procedure (e.g., transmission of a signal including a preamble PRACH and PUSCH) and a 4-way random access procedure (eg, transmitting a signal including the PRACH preamble but not including the PUSCH). In other words, the terminal 200 determines whether to apply the 2-way random access procedure or apply fallback to the 4-way random access procedure.

[0082] For example, terminal 200 calculates the transmit power for the PRACH preamble and the transmit power for the PUSCH in Message A. transmission powers greater than or equal to the thresholds), the terminal 200 transmits the PRACH and PUSCH preamble (in other words, selects the 2-way random access procedure) during message A transmission. On the other hand, when at least one of the calculated PRACH preamble transmission power value and the calculated PUSCH transmission power value does not satisfy the corresponding allowable value (in other words, when the transmission power value is less than the corresponding threshold), the terminal 200 during transmission of message A transmits a preamble PRACH without transmitting PUSCH (in other words, chooses to return to the 4-round random access procedure). It should be noted that allowable values (eg, thresholds) are transmit powers for base station 100 to receive signals, eg, PRACH and PUSCH preambles, with sufficient reliability.

[0083] FIG. 6 shows an example of a random access procedure in accordance with the present invention.

[0084] The terminal 200 first calculates the transmit power PPRACH for the PRACH preamble and the transmit power P _PUSCH for the PUSCH (which can also be expressed as "_P'PUSCH") in message A. Examples of a calculation method for calculating transmit powers include a method based on on the open-loop control described above. For example, terminal 200 calculates the transmit power PPRACH for the PRACH preamble and the transmit power P _PUSCH for the PUSCH as follows:

[0085] Here, for example, a case will be described in which the transmit power values before scaling by the maximum transmit powers P _CMAX that the terminal 200 can transmit (for example, the values corresponding to the second terms of the minimum function in Equations 4 and five). For example, when the transmit power value is greater than the allowable value or equal to the allowable value (in other words, the threshold value), the signal is received at the base station 100 with sufficient reliability. On the other hand, when the transmission power value is smaller than the allowable value (in other words, the threshold value), the signal is not reliably received at the base station 100. It should be noted that the values configured as valid values are not limited to these values and may be other values.

[0086] For example, in FIG. 6, terminal 200 may transmit the PRACH preamble and PUSCH with transmit powers that are allowable values (thresholds) when each of the transmit power P _PRACH for the PRACH preamble and the transmit power P' _PUSCH for PUSCH is less than or equal to P _CMAX . Accordingly, the terminal 200 determines that the base station 100 can receive both the PRACH and PUSCH preamble signals with sufficient reliability, and determines that the transmission powers for message A are within acceptable limits. In this case, the terminal 200 performs a 2-way random access procedure. In other words, terminal 200 transmits the PRACH and PUSCH preamble in message A.

[0087] On the other hand, for example, in FIG. 6, when the value of the transmit power before scaling by P _CMAX (P' _PUSCH in FIG. 6) exceeds P _CMAX , the terminal 200 scales the transmit power (P _PUSCH in FIG. 6) down to P _CMAX . Due to scaling, terminal 200 cannot transmit PUSCH with a transmission power value P' _PUSCH that is a valid value (threshold) when P' _PUSCH exceeds P _CMAX . Thus, the terminal 200 determines that one of the transmit powers for the PRACH and PUSCH preamble does not satisfy the corresponding allowable value. In this case, the terminal 200 performs a 4-way random access procedure. In other words, terminal 200 sends a PRACH preamble without PUSCH in message A.

[0088] It is understood that, according to the present embodiment, the terminal 200 selects a 2-round random access procedure (in other words, PRACH and PUSCH preamble transmission) or a 4-round random access procedure (in other words, PRACH preamble transmission without PUSCH transmission) in depending on the channel state between the base station 100 and the terminal 200. For example, when the channel state is bad and the transmission quality does not satisfy the predetermined reliability, the terminal 200 selects the 4-way random access procedure and does not transmit the PUSCH. Thus, PUSCH collisions with other terminals can be reduced.

[0089] It should be noted that, in the present embodiment, the transmission power calculation method may be the 4-way random access transmit power control open loop control method described above, or may be another method. For example, terminal 200 may calculate the transmit power for the PRACH preamble according to Equation 4, and may configure, as the transmit power for PUSCH, a value obtained by adding an offset value (eg, a parameter configured by the base station) to the calculated transmit power for the PRACH preamble.

[0090]

[Uplink signal transmission timing]

Next, the present embodiment will be described in connection with the timing with which terminal 200 transmits an uplink signal (eg, message A). The timings 1-3 described below are assumed as, for example, the transmission timing of the uplink signal.

[0091] <Sync 1>

Timing 1 is the timing at which terminal 200 performs the initial transmission of message A.

[0092] The terminal 200 sends message A to initialize the 2-way random access procedure. Message A includes, for example, a PRACH and PUSCH preamble.

[0093] However, at timing 1, when either one of the PRACH preamble transmission power value or the PUSCH transmission power value in message A does not satisfy the corresponding valid value, the terminal 200 during transmission of message A transmits the PRACH preamble without transmitting PUSCH (in other words, chooses to return to the 4-step random access procedure).

[0094] <Sync 2>

Timing 2 is the timing at which terminal 200 receives message A.

[0095] When message A is detected and correctly decoded, base station 100 transmits message B. Message B includes, for example, a RACH response (RAR) and identification information about terminal 200 (eg, UE ID). When the terminal 200 successfully decodes the B message including the corresponding UE ID of the terminal 200, the terminal 200 determines that the random access procedure is successful.

[0096] The base station 100 transmits message B, and in the case where the PRACH preamble of message A is detected, but the data section cannot be decoded. In this case, at this stage, the base station 100 cannot identify the terminal 200 that transmitted the PRACH preamble. Thus, message B includes, for example, a response to a RACH (RAR). The RAR may include, for example, information requesting the terminal 200 that transmitted the PRACH preamble to retransmit message A (in other words, information about retransmission of message A). For message A retransmission information included in RAR, Option 1 and Option 2 are assumed.

[0097] <Option 1>

In option 1, the RAR includes an indication (eg, a Negative Acknowledgment (NACK)) requesting retransmission from the terminal 200 that transmitted the PRACH preamble detected by the base station 100. However, the RAR does not include resource information for retransmitting the message. A. Upon receiving a message B including an indication requesting retransmission of the PRACH preamble transmitted by terminal 200, terminal 200 transmits message A again (in other words, retransmits message A). Message A to be retransmitted includes, for example, a PRACH and PUSCH preamble.

[0098] However, at timing 2, when at least one of the transmission power value of the PRACH preamble and the transmission power value of PUSCH in the message A to be retransmitted does not satisfy the corresponding valid value, the terminal 200 during the transmission of message A transmits the PRACH preamble without transmitting the PUSCH ( in other words, returns to the 4-round random access procedure).

[0099] <Option 2>

In option 2, the RAR includes PUSCH resource information in an indication requesting retransmission from the terminal 200 that transmitted the PRACH preamble detected by the base station 100. related to PUSCH resources, terminal 200 retransmits message A. Here, in retransmission of message A, terminal 200 transmits PUSCH without transmitting a PRACH preamble. In other words, message A does not include a PRACH preamble, but does include a PUSCH.

[0100] However, at timing 2, when the power value of the PUSCH to be retransmitted does not satisfy the corresponding allowable value, the terminal 200 switches to PRACH preamble transmission without PUSCH transmission during transmission of message A (in other words, chooses to return to the 4-round random access procedure) .

[0101] <Sync 3>

Timing 3 is timing in which terminal 200 retransmits message A when terminal 200 does not receive message B within a predetermined period of time (for example, within a receive window for message B, etc.) after message A has been transmitted.

[0102] When the base station 100 fails to detect message A (eg, the PRACH preamble), the base station 100 does not include information addressed to the terminal 200 that sent the message A in the message B. When the terminal 200 that sent the message A does not receive the message B, including information addressed to terminal 200, within a predetermined time period (e.g., during message B receive window) after message A is transmitted, terminal 200 retransmits message A.

[0103] However, at timing 3, when at least one of the transmission power value of the PRACH preamble and the transmission power value of PUSCH in the message A to be retransmitted does not satisfy the corresponding valid value, the terminal 200 during the transmission of message A transmits the PRACH preamble without transmitting the PUSCH ( in other words, returns to the 4-round random access procedure).

[0104] Uplink signal timings (eg, timings 1-3) have been described above.

[0105] Further, as an example, in FIG. 7 shows a flowchart of a processing example at base station 100 and terminal 200 in accordance with the present invention. FIG. 7 shows an example of process processing at timing 1 (during initial transmission) and timing 2 (during retransmission) among the uplink signal transmission timings described above.

[0106] FIG. 7, the base station 100 transmits (ST101) the transmission parameter of the message A to the terminal 200. Examples of the transmission parameter of the message A may include parameters related to transmission power control of the PRACH and PUSCH preamble of the message A.

[0107] The terminal 200 obtains (ST102) information about the transmission parameter of the message A indicated by the base station 100. The terminal 200 calculates (ST103) the transmission power for the PRACH preamble and the transmission power of the PUSCH message A, for example, based on the transmission parameter of the message A.

[0108] The terminal 200 compares (ST104) the calculated transmission powers with valid values, and based on the result of the comparison, selects (ST105) one of the 2-round random access procedure and the 4-round random access procedure. For example, when at least one of the transmit power for the PRACH preamble and the transmit power for PUSCH does not satisfy the corresponding allowable value (in other words, when at least one transmit power is less than a threshold), terminal 200 selects a 4-way access procedure. On the other hand, when the transmit power for the PRACH preamble and the transmit power for the PUSCH both satisfy the allowable values (in other words, when both transmit powers are greater than or equal to the threshold values), the terminal 200 selects the 2-way random access procedure.

[0109] The terminal 200 generates (ST106) message A based on the selected random access procedure. For example, after selecting the 2-round random access procedure, the terminal 200 generates an A message including the PRACH and PUSCH preamble. On the other hand, after selecting the 4-round random access procedure, the terminal 200 generates an A message, for example, not including the PUSCH but including the PRACH preamble.

[0110] The terminal 200 transmits (ST107) the generated message A to the base station 100 .

[0111] The base station 100 detects (ST108) the A message (eg, PRACH preamble) transmitted by the terminal 200. In addition, when the detected message A is a 2-way random access message A, the base station 100 decodes (ST109) the PUSCH, included in message A.

[0112] The base station 100 generates (ST110) message B. Meanwhile, in FIG. 7, it is assumed that the base station 100 detects the PRACH preamble but cannot decode the PUSCH. In this case, the base station 100 generates message B including an indication related to retransmission of message A (eg, a retransmission request). Base station 100 transmits (ST111) message B to terminal 200.

[0113] Terminal 200 receives (ST112) message B from base station 100, and receives (ST113) an indication related to retransmission of message A included in message B. Accordingly, terminal 200 determines retransmission of message A (in other words, retransmission with sync 2 above).

[0114] For example, in option 1 at timing 2 described above, terminal 200 includes a PRACH and PUSCH preamble in message A to be retransmitted.

[0115] However, similar to the processes at synchronization 1 (e.g., processes ST102-ST106), terminal 200 determines the random access procedure to be applied to retransmit message A based on the transmission powers for message A.

[0116] For example, the terminal 200 calculates (ST114) the transmit power for the PRACH preamble and the transmit power for the PUSCH message A, and compares (ST115) the calculated transmit powers with valid values. In doing so, terminal 200 may, for example, increase (power ramp) the transmit power for at least one of the PRACH and PUSCH preambles to a transmit power that is greater than the original transmission transmit power (eg, timing 1) (see, for example, option implementations 2 or 4 described below).

[0117] As in step ST105, the terminal 200 selects (ST116) one of the 2-stage random access procedure and the 4-stage random access procedure based on the comparison result. Based on the selected random access procedure, the terminal 200 generates (ST117) a message A for retransmission, and transmits (ST118) (in other words, retransmits) the message A to the base station 100.

[0118] It should be noted that in FIG. 7 describes option 1 in timing 2 (the case in which the PRACH preamble and PUSCH are included in the retransmitted message A), but option 2 in timing 2 (the case in which the PRACH preamble is included in the retransmitted message A but not PUSCH).

[0119] Further, as another example, in FIG. 8 shows a flowchart of a processing example at base station 100 and terminal 200 in accordance with the present invention. FIG. 8 shows an example of process processing at timing 1 (during initial transmission) and timing 3 (during retransmission) among the uplink signal transmission timings described above.

[0120] FIG. 8 the same processes as in FIG. 7 (for example, the process at synchronization 1 (for example, processes ST101-ST107)) have the same item numbers and their descriptions are omitted.

[0121] FIG. 8, it is assumed by way of example that base station 100 fails to detect (ST108a) message A (eg, including the PRACH preamble) from terminal 200. In this case, base station 100 does not include information addressed to the terminal in message B (not shown). 200 that sent message A. In other words, terminal 200 cannot receive message B from base station 100.

[0122] After transmitting (ST106) message A, terminal 200 determines (ST201) whether or not message B has been received within a predetermined period (e.g., message B receive window) (in other words, whether the timer for receiving message B has expired or not). After the timer for receiving message B has elapsed, terminal 200 determines to retransmit message A (in other words, retransmission with timing 3 described above).

[0123] For example, terminal 200 includes a PRACH and PUSCH preamble in message A to be retransmitted.

[0124] However, similar to processes at synchronization 1 (e.g., processes ST102-ST106), terminal 200 determines the random access procedure to be applied to retransmit message A based on the transmission powers for message A.

[0125] For example, the terminal 200 calculates (ST202) the transmit power for the PRACH preamble and the transmit power for the PUSCH message A, and compares (ST203) the calculated transmit powers with valid values. In doing so, terminal 200 may, for example, increase (power ramp) the transmit power for at least one of the PRACH and PUSCH preambles to a transmit power that is greater than the original transmission transmit power (eg, timing 1) (see, for example, option implementations 2 or 4 described below).

[0126] As in step ST105, the terminal 200 selects (ST204) one of the 2-stage random access procedure and the 4-stage random access procedure based on the comparison result. Based on the selected random access procedure, the terminal 200 generates (ST205) an A message and transmits (ST206) (in other words, retransmits) the A message to the base station 100.

[0127] As described above, in the present embodiment, when at least one of the transmission power for the PRACH preamble and the transmission power for the PUSCH of message A does not satisfy the corresponding allowable value when performing the 2-way random access procedure, the terminal 200 at the time of transmitting the message A transmits the PRACH preamble without transmitting PUSCH. In other words, the terminal 200 returns from the 2-way random access procedure to the 4-way random access procedure when the quality of message A (eg, transmit power) does not satisfy the allowable value.

[0128] Thus, for example, when the transmission quality of the PUSCH cannot meet a given reliability, the terminal 200 can avoid transmitting the PUSCH during transmission of the 2-way random access message A to reduce the increase in interference to other terminals in the PUSCH resources.

[0129] Accordingly, according to the present embodiment, the efficiency of random access processing can be improved.

[0130] It should be noted that Embodiment 1 has been described in which terminal 200 calculates the transmit power for the PRACH preamble and the transmit power for the PUSCH, and compares these transmit powers with allowable values. However, the present invention is not limited to this, and, for example, the terminal 200 may calculate the transmit power for the PUSCH without calculating the transmit power for the PRACH preamble, and may compare the calculated transmit power with a corresponding allowable value. In other words, the terminal 200 may select one of the 2-round random access procedure and the 4-round random access procedure based on the transmit power for the PUSCH.

[0131] (Modification 1 of Embodiment 1)

The values used by the terminal 200 as references for selecting one of the 2-way random access procedure (in other words, PRACH and PUSCH preamble transmission) and 4-way random access procedure (in other words, PRACH preamble transmission without PUSCH transmission) are not limited to the values transmission power, and may be other channel quality information between base station 100 and terminal 200. in the passband, the Signal to Noise Ratio (SNR) for the received signal, or the Signal to Interference and Noise Ratio (SINR) for the received signal). Since the transmission power calculation method in NR is for bandwidth loss compensation, the terminal 200 may select one of the 2-round random access procedure and the 4-round random access procedure according to the channel state. Thus, it is possible to reduce unnecessary PUSCH transmission by the terminal 200 for which the transmission quality cannot meet a given reliability due to bad channel conditions, so as to reduce unnecessary collisions between PUSCHs.

[0132] In addition, the synchronization signal in NR consists of, for example, a primary synchronization signal (Primary Synchronization Signal, PSS) and a secondary synchronization signal (Secondary Synchronization Signal, SSS) (see, for example, NPL 1). For example, in the high frequency band of 6 GHz and above, the application of transmission beamforming at base station 100 is expected to guarantee a usable communication distance and area between base station 100 and terminal 200. In NR, a synchronization and broadcast signal channel (e.g., a physical broadcast channel ( Physical Broadcast Channel, PBCH)) is defined as one block (eg, referred to as the "SS/PBCH" block). For example, one SS/PBCH block is transmitted by transmission beams in one direction, and a configuration (beam swing) with daisy chaining and beam transmission is also supported. However, for a lower frequency band, etc., which is lower than the aforementioned high frequency band, a configuration in which one SS/PBCH block is transmitted with a single beam pattern without applying beam sweep can also be used.

[0133] When applying beamforming to the SS/PBCH block, the base station 100 applies, for example, a receive beamforming equivalent to that applied to the SS/PBCH block to receive the RACH from the terminal 200 that received the SS/PBCH block. For example, terminal 200 transmits a PRACH signal based on the PRACH preamble resource associated with the detected SS/PBCH block (see, for example, NPL 6). In addition, terminal 200 may, for example, be configured to measure using a Channel State Information Reference Signal (CSI-RS), and the CSI-RS and the PRACH preamble resource may be associated with each other (see , for example, NPL 6).

[0134] For example, in a 4-round random access procedure, terminal 200 measures the reception quality (e.g., Synchronization Signal Reference Signal Received Power, SS-RSRP) or Channel State Information received reference signal power. Reference Signal Received Power, CSI-RSRP)) of the SS/PBCH or CSI-RS unit. Then, when there is more than one SS/PBCH or CSI-RS block for which the SS-RSRP or CSI-RSRP is greater than or equal to the threshold, terminal 200 may select one SS/PBCH or CSI-RS block from among those SS blocks. /PBCH or CSI-RS and select a PRACH preamble from the set of potentially eligible PRACH preamble resources associated with the selected SS/PBCH or CSI-RS block. It should be noted that terminal 200 may, for example, select any one SS-RSRP or CSI-RSRP when there is no SS/PBCH or CSI-RS block for which the SS-RSRP or CSI-RSRP is greater than or equal to the threshold.

[0135] In addition, for example, in a 2-way random access procedure, terminal 200 may measure the reception quality of an SS/PBCH or CSI-RS block (eg, SS-RSRP or CSI-RSRP), and if there is more than one SS/ PBCH or CSI-RS for which the SS-RSRP or CSI-RSRP is greater than or equal to the threshold, terminal 200 may select one SS/PBCH or CSI-RS block from among those SS/PBCH or CSI-RS blocks and execute 2 -staged random access procedure. That is, the terminal 200 may transmit an A message including a PRACH preamble and a PUSCH using the PRACH preamble resources associated with one of a plurality of SS/PBCH or CSI-RS blocks for which the reception quality is greater than or equal to the threshold. .

[0136] On the other hand, when there is no SS/PBCH or CSI-RS block for which the reception quality (eg, SS-RSRP or CSI-RSRP) is greater than or equal to the threshold, terminal 200 may, for example, select any block SS/PBCH or CSI-RS and return to the 4-way random access procedure. That is, when there is no signal for which the reception quality is greater than or equal to the threshold among the plurality of SS/PBCH or CSI-RS blocks, terminal 200 may transmit an A message including a PRACH preamble but not including any PUSCH using PRACH preamble resources associated with one of the plurality of SS/PBCH or CSI-RS blocks.

[0137] According to Modification 1, a higher quality beam pattern can be selected for the 2-way random access procedure. In this way, it is possible to reduce unnecessary collisions between PUSCHs by the terminal 200 for which the transmission quality cannot meet the predetermined reliability due to the degraded transmission quality of the PUSCH and the poor channel condition.

[0138] (Modification 2 of Embodiment 1)

In modification 1, the threshold value for SS-RSRP or CSI-RSRP may be different for 4-way random access procedure and 2-way random access procedure.

[0139] For example, for a 2-round random access procedure, the threshold for SS-RSRP or CSI-RSRP may be set higher than for a 4-round random access procedure. In this case, a higher quality beam pattern is selected for the 2-way random access procedure. In this way, it is possible to reduce unnecessary collisions between PUSCHs by the terminal 200 for which the transmission quality cannot meet the predetermined reliability due to the degraded transmission quality of the PUSCH and the poor channel condition.

[0140] (Modification 3 of Embodiment 1)

The size of the transport block (Transport Block Size, TBS) for the transmission of the PUSCH message A does not have to be fixed. For example, terminal 200 may select one TBS from a plurality of TBSs based on the UP data (eg, amount of user plane data) actually transmitted by terminal 200.

[0141] In this case, the terminal 200 may calculate the transmit power for the PUSCH in message A, for example, based on the selected TBS, and scale the TBS (in other words, select a smaller TBS) of the PUSCH when the calculated transmit power value does not satisfy the allowable value (in other words when the calculated transmit power value is less than the threshold value). Then, terminal 200 may calculate the transmit power for the PUSCH for which the TBS is scaled, and may transmit the PRACH and PUSCH preamble using the scaled TBS in message A when the calculated transmit power satisfies the allowable value. This method allows the terminal 200 to transmit a reliable PUSCH for as long as possible to reduce the delay caused by returning to the 4-round random access procedure. It should be noted that when the TBS cannot be scaled (a smaller TBS cannot be selected), the terminal 200 may transmit the PRACH preamble without transmitting the PUSCH during message A transmission (in other words, return to the 4-round random access procedure).

[0142] (Embodiment 2)

Since the base station and the terminal according to the present embodiment have the same basic configurations as the base station 100 and the terminal 200 according to Embodiment 1, they will be described with reference to FIG. 4 and 5.

[0143] In the present embodiment, when timing the retransmission of an uplink signal (e.g., message A) in a 2-way random access procedure, the terminal 200 linearly increases the transmit power for the PUSCH (in other words, increases the transmit power compared to the transmit power during previous transmission) without changing the transmit power for the PRACH preamble of message A compared to the transmit power during the previous transmission.

[0144] In addition, when the PRACH preamble transmit power value and the PUSCH linearly increased transmit power value both satisfy the allowable values (for example, the transmit powers are such that the base station 100 receives the PRACH and PUSCH preamble signals with sufficient reliability), the terminal 200 during retransmission transmitting the message A transmits the PRACH and PUSCH preamble (in other words, selects the 2-way random access procedure). On the other hand, when at least one of the transmission power value of the PRACH preamble and the linearly increased transmission power value of the PUSCH does not satisfy the corresponding allowable value, the terminal 200, during message A retransmission, transmits the PRACH preamble without transmitting the PUSCH (in other words, chooses to return to 4 -staged random access procedure).

[0145] FIG. 9 shows an example of a random access procedure in accordance with the present invention.

[0146] As shown in FIG. 9, when message A is retransmitted, terminal 200 ramps up the transmit power for PUSCH in message A.

[0147] Terminal 200 then calculates the transmit power for the PRACH preamble and the uplink transmit power for PUSCH in message A. For example, terminal 200 may configure as the linearly increased transmit power the value obtained by adding an offset value (e.g., configured by base station 100) to the transmit power for PUSCH computed before the ramp.

[0148] Here, for example, a case will be described in which the transmit power values before scaling by the maximum transmit powers P _CMAX with which the terminal 200 can transmit (for example, the values corresponding to the second terms of the minimum function in Equations 4 and 5) (in other words, threshold values). It should be noted that the values configured as valid values are not limited to these values and may be other values.

[0149] For example, in FIG. 9, terminal 200 may transmit the PRACH preamble and PUSCH with transmit powers that are allowable values (thresholds) when each of the transmit power P _PRACH for the PRACH preamble and the transmit power P'PUSCH for _PUSCH is less than or equal to P _CMAX . Accordingly, the terminal 200 determines that the base station 100 can receive both the PRACH and PUSCH preamble signals with sufficient reliability, and determines that the transmission powers for message A are within acceptable limits. In this case, the terminal 200 performs a 2-way random access procedure. In other words, terminal 200 transmits the PRACH and PUSCH preamble in message A.

[0150] On the other hand, for example, in FIG. 9, when the value of the transmit power before scaling by P _CMAX (P _'PUSCH in FIG. 9) exceeds P _CMAX , the terminal 200 scales the transmit power (P _PUSCH in FIG. 9) down to P _CMAX . Due to scaling, terminal 200 cannot transmit PUSCH with a transmit power value P _'PUSCH that is a valid value (threshold) when P _'PUSCH exceeds P _CMAX . Thus, the terminal 200 determines that one of the transmit powers for the PRACH and PUSCH preamble does not satisfy the corresponding allowable value. In this case, the terminal 200 performs a 4-way random access procedure. In other words, terminal 200 sends a PRACH preamble without PUSCH in message A.

[0151] It is understood that, according to the present embodiment, the terminal 200 selects a 2-round random access procedure (in other words, PRACH and PUSCH preamble transmission) or a 4-round random access procedure (in other words, PRACH preamble transmission without PUSCH transmission) in depending on the channel state between the base station 100 and the terminal 200. For example, when the channel state is bad and the transmission quality does not satisfy the predetermined reliability, the terminal 200 selects the 4-way random access procedure and does not transmit the PUSCH. Thus, PUSCH collisions with other terminals can be reduced.

[0152] In addition, according to the present embodiment, terminal 200 can improve the reception quality of the PUSCH in message A by ramping up the transmit power of the PUSCH during message A retransmission.

[0153] In addition, the present embodiment is effective, for example, when the transmission timing of the uplink signaling described above is “timing 2”, and the information requesting retransmission included in message B (eg, RAR) is “ option 1". Terminal 200 transmits the PRACH preamble and PUSCH in the retransmitted message A. At this time, terminal 200 can know, based on the RAR reception, that the PRACH preamble was successfully detected at base station 100. In this case, terminal 200 does not change the transmission power for the PRACH preamble, for example, as shown in FIG. 9. Thus, an unnecessary increase in transmission power for the PRACH preamble can be prevented.

[0154] (Modification 1 of Embodiment 2)

The TBS for sending the PUSCH message A need not be fixed. For example, terminal 200 may select one TBS from a plurality of TBSs based on the UP data (eg, amount of user plane data) actually transmitted by terminal 200.

[0155] In this case, terminal 200 may scale the PUSCH TBS (eg, select a smaller TBS), for example, when the linearly increased PUSCH transmission power value does not satisfy the allowable value. Then, terminal 200 may recalculate the transmit power for the PUSCH for which the TBS is scaled, and may transmit the PRACH and PUSCH preamble using the scaled TBS in message A when the calculated transmit power satisfies the allowable value. This method allows the terminal 200 to transmit a reliable PUSCH for as long as possible to reduce the delay caused by returning to the 4-round random access procedure. It should be noted that when the TBS cannot be scaled (a smaller TBS cannot be selected), the terminal 200 may transmit the PRACH preamble without transmitting the PUSCH during message A transmission (in other words, return to the 4-round random access procedure).

[0156] (Modification 2 of Embodiment 2)

In the case where the terminal 200 performs the 2-way random access procedure, and in the case where the terminal 200 performs the 4-way random access procedure, different values can be configured for the increase amount of the PUSCH transmission power value (in other words, the power ramp offset). .

[0157] (Modification 3 of Embodiment 2)

When the terminal 200 returns to the 4-way random access procedure after repeatedly applying the power ramp in the 2-way random access procedure, the terminal 200 may, as a transmission power, permanently configure the transmission power to which the power ramp has been applied in the 2-way random access procedure. . Thus, the terminal 200 can, for example, prevent the increase in the delay caused by the recovery, after the return operation, of the transmission power to the transmission power of the original transmission in the 4-way random access procedure, and resulting in unnecessary transmission of the PRACH preamble.

[0158] (Embodiment 3)

Since the base station and the terminal according to the present embodiment have the same basic configurations as the base station 100 and the terminal 200 according to Embodiment 1, they will be described with reference to FIG. 4 and 5.

[0159] In the present embodiment, when timing the retransmission of an uplink signal (eg, message A) in a 2-round random access procedure, the terminal 200 continues the 2-round random access procedure without returning to the 4-round random access procedure when the terminal 200 the TPC command from the base station 100 is indicated. In other words, when the terminal 200 is indicated with the TPC command (for example, a parameter related to transmit power control) from the base station 100 when transmitting the A message, the terminal 200 transmits the A message including the PRACH preamble and the PUSCH depending on the TPC command.

[0160] The present implementation is effective, for example, when the transmission timing of the uplink signal described above is "timing 2" and the information requesting retransmission included in message B (e.g., RAR) is "option 2" . The base station 100 uses the RAR to indicate to the terminal 200 that transmitted the detected PRACH preamble the PUSCH resource information as an indication requesting retransmission. Here, in addition to the PUSCH resource information, the base station 100 may include a TPC command in the UL grant included in the RAR. Through the TPC command, the base station 100 can precisely control the transmit power of the terminal 200.

[0161] In addition, for example, by managing PUSCH resources between multiple terminals 200, base station 100 can prevent contention between PUSCH resources for retransmission. Therefore, in the present embodiment, it is not necessary to return to the 4-round random access procedure in order to prevent contention between PUSCH resources. Thus, the latency can be reduced. In addition, according to the present embodiment, it is possible to prevent discrepancies between the base station 100 and the terminal 200 regarding the presence or absence of PUSCH transmission.

[0162] (Modifications of Embodiment 3)

In Embodiment 3, the TPC command included in the RAR is not limited to an indication instructing to increase or decrease transmission power, and may include, for example, an indication by which the base station 100 directs the terminal 200 to retransmit the 2-way random access message A (in other words, send the PRACH and PUSCH preamble) or return to the 4-round random access procedure. For example, if there are a large number of terminals 200 that retransmit the PUSCH and the terminals 200 cannot be satisfied simultaneously, the base station 100 may offload some terminals 200 to the PUSCH resources of a 4-way random access procedure or a 2-way random access procedure.

[0163] (Embodiment 4)

Since the base station and the terminal according to the present embodiment have the same basic configurations as the base station 100 and the terminal 200 according to Embodiment 1, they will be described with reference to FIG. 4 and 5.

[0164] In the present embodiment, when timing the retransmission of an uplink signal (e.g., message A) in a 2-way random access procedure, terminal 200 linearly increases the transmission power for both the PRACH preamble and the PUSCH of message A (in other words, increases transmit power compared to the transmit powers during the previous transmission).

[0165] In addition, when the PRACH preamble transmit power ramp and the PUSCH transmit power ramp both satisfy the allowable values (for example, the transmit powers are such that the base station 100 receives the PRACH and PUSCH preamble signals with sufficient reliability), the terminal 200 message retransmission time A transmits the PRACH and PUSCH preamble (in other words, selects the 2-way random access procedure). On the other hand, when at least one of the PRACH preamble transmit power ramp and the PUSCH transmit power ramp does not satisfy the corresponding allowable value, the terminal 200, during message A retransmission, transmits the PRACH preamble without PUSCH transmission (in other words, selects a return to the 4-step random access procedure).

[0166] FIG. 10 shows an example of a random access procedure in accordance with the present invention.

[0167] As shown in FIG. 10, during message A retransmission, terminal 200 linearly increases the transmit power for the PRACH preamble and the transmit power for PUSCH in message A.

[0168] Next, terminal 200 calculates the PRACH preamble transmit power ramp and the PUSCH transmit power ramp. For example, terminal 200 may configure as ramped transmit powers the values obtained by adding an offset value (eg, configured by base station 100) to the transmit powers calculated before the ramp.

[0169] Here, for example, a case will be described in which the transmit power values before scaling by the maximum transmit powers P _CMAX with which the terminal 200 can transmit (for example, the values corresponding to the second terms of the minimum function in Equations 4 and five). It should be noted that the values configured as valid values are not limited to these values and may be other values.

[0170] For example, in FIG. 10, terminal 200 may transmit the PRACH preamble and PUSCH with transmit powers that are allowable values (thresholds) when each of the transmit power P _PRACH for the PRACH preamble and the transmit power P'PUSCH for _PUSCH is less than or equal to P _CMAX . Accordingly, the terminal 200 determines that the base station 100 can receive both the PRACH and PUSCH preamble signals with sufficient reliability, and determines that the transmission powers for message A are within acceptable limits. In this case, the terminal 200 performs a 2-way random access procedure. In other words, terminal 200 transmits the PRACH and PUSCH preamble in message A.

[0171] On the other hand, for example, in FIG. 10, when the transmit power value before scaling by P _CMAX (P _'PUSCH in FIG. 10) exceeds P _CMAX , terminal 200 downscales the transmit power (P _PUSCH in FIG. 10) to P _CMAX . Due to scaling, terminal 200 cannot transmit PUSCH with a transmit power value P _'PUSCH that is a valid value (threshold) when P _'PUSCH exceeds P _CMAX . Thus, the terminal 200 determines that one of the transmit powers for the PRACH and PUSCH preamble does not satisfy the corresponding allowable value. In this case, the terminal 200 performs a 4-way random access procedure. In other words, terminal 200 sends a PRACH preamble without PUSCH in message A.

[0172] It is understood that, according to the present embodiment, the terminal 200 selects a 2-round random access procedure (in other words, PRACH and PUSCH preamble transmission) or a 4-round random access procedure (in other words, PRACH preamble transmission without PUSCH transmission) in depending on the channel state between the base station 100 and the terminal 200. For example, when the channel state is bad and the transmission quality does not satisfy the predetermined reliability, the terminal 200 selects the 4-way random access procedure and does not transmit the PUSCH. Thus, PUSCH collisions with other terminals can be reduced.

[0173] According to the present embodiment, terminal 200 can improve the reception quality of message A by linearly increasing the transmit power for the PRACH preamble and the transmit power for PUSCH during message transmission. A.

[0174] In addition, the present implementation is effective, for example, when the uplink signal transmission timing of the above-described terminal is “timing 3”. Terminal 200 increases transmit powers for both the PRACH preamble and PUSCH because base station 100 failed to detect an A message. Accordingly, reception quality for both the PRACH preamble and PUSCH can be improved at the base station.

[0175] (Modification 1 of Embodiment 4)

The TBS for sending the PUSCH message A need not be fixed. For example, terminal 200 may select one TBS from a plurality of TBSs based on the UP data (eg, amount of user plane data) actually transmitted by terminal 200.

[0176] In this case, terminal 200 may scale the PUSCH TBS (eg, select a smaller TBS), for example, when the linearly increased PUSCH transmission power value does not satisfy the allowable value. Then, terminal 200 may recalculate the transmit power for the PUSCH for which the TBS is scaled, and may transmit the PRACH and PUSCH preamble using the scaled TBS in message A when the calculated transmit power satisfies the allowable value. This method allows the terminal 200 to transmit a reliable PUSCH for as long as possible to reduce the delay caused by returning to the 4-round random access procedure. It should be noted that when the TBS cannot be scaled (a smaller TBS cannot be selected), the terminal 200 may transmit the PRACH preamble without transmitting the PUSCH during message A transmission (in other words, return to the 4-round random access procedure).

[0177] (Modification 2 of Embodiment 4)

The method for calculating linearly increased transmission powers, for example, allows to calculate as linearly increased transmission powers the values obtained by adding an offset value (a parameter configured by the base station) to the transmission powers calculated before the ramp. Here, different power ramp offset values (power ramp step) can be configured for the 4-round random access procedure and the 2-round access procedure. For example, a 2-way random access procedure is expected to be provided for use cases that require low latency. Accordingly, the power ramp step is larger in the 2-stage random access procedure than in the 4-stage random access procedure. Such a power ramp step avoids multiple transmissions to reduce delay. The power ramp steps can be configured independently between the 4-way random access procedure and the 2-way random access procedure, or a method can be used in which the power ramp step for the 2-way access procedure can be configured as a power ramp step for a 4-round random access procedure by multiplying by a factor (×X) or adding an offset (+Y) . The X or Y value may be a parameter configured by the base station 100.

[0178] (Modification 3 of Embodiment 4)

When the terminal 200 returns to the 4-way random access procedure after repeatedly applying the power ramp in the 2-way random access procedure, the terminal 200 can permanently configure the transmission powers to which the power ramp has been applied in the 2-way random access procedure as the transmission power. . That is, the terminal 200 may configure the increased transmit powers in the 2-way random access procedure as the transmission powers for message A in the 4-way random access procedure when message A is retransmitted based on the 4-way random access procedure after the message A was transferred based on a 2-round random access procedure.

[0179] In this way, the terminal 200 can, for example, prevent the increase in the delay caused by the recovery, after the return operation, of the transmission powers to the transmission powers of the original transmission in the 4-round random access procedure, and resulting in unnecessary transmission of the PRACH preamble.

[0180] (Modification 4 of Embodiment 4)

In the 2-round random access procedure, terminal 200 may configure an upper limit value for the number of transmissions (or retransmissions) of message A. For example, when the number of transmissions exceeds the upper limit value of the counter, terminal 200 may return to the 4-round random access procedure. Thus, frequent PUSCH retransmissions to prevent PUSCH collisions can be avoided.

[0181] (Embodiment 5)

As described above, the method for calculating transmission powers in the 2-round random access procedure may apply open-loop control (see, for example, Equations 4 and 5) in which the transmission power control is used in the 4-round random access procedure.

[0182] For example, in the transmission power control for the PRACH preamble, open loop control is applied in both the 2-round random access procedure and the 4-round random access procedure. Thus, it is assumed that the same calculation method as illustrated in Equation 1 or 4 is applied.

[0183] However, in the 2-way random access procedure, the PUSCH is included in message A. Thus, the robustness to the difference in transmission timing between terminals is low. Therefore, it is expected that the 2-way random access procedure will be applied in a small cell environment. Accordingly, in the 2-round random access procedure, the RACH format having a shorter PRACH preamble length (eg, fewer symbols) is more likely to be used than in the 4-round random access procedure.

[0184] At the same time, the 4-round random access procedure is expected to be applied to cover large area areas. Accordingly, in a 4-round random access procedure, it is more likely to use a RACH format having a longer PRACH preamble (eg, more symbols) than in a 2-round random access procedure.

[0185] Here, when the transmission power per symbol is the same, the longer the PRACH preamble length, the more power is added. For this reason, in the 4-way random access procedure in which the length of the RACH preamble is longer, the base station can receive the PRACH preamble with a higher received signal strength. On the other hand, in the 2-way random access procedure in which the RACH preamble length is shorter, there is a possibility that sufficient received power may not be obtained at the base station.

[0186] Therefore, in the present implementation, different received power targets PPRACH_target are used to calculate the transmission powers for the 2-round random access procedure and the 4-round random access procedure for the PRACH preamble.

[0187] It should be noted that since the base station and terminal according to the present embodiment have the same basic configurations as the base station 100 and terminal 200 according to Embodiment 1, they will be described with reference to FIG. 4 and 5.

[0188] <Option 1>

In option 1, for each of the 2-way random access procedure and the 4-way random access procedure for the PRACH preamble, an independent received power target value PPRACH_target is configured.

[0189] For example, the PPRACH transmit power for the PRACH preamble is calculated as follows:

P _PRACH = min{P _CMAX , P _{PRACH_target} (x) + PL} ... (Equation 6).

[0190] Here, x is a parameter for distinguishing between a 2-stage random access procedure and a 4-stage random access procedure. For example, x=0 represents a 2-round random access procedure, and x=1 represents a 4-round random access procedure.

[0191] For example, in Equation 6, PPRACH_target(0) and PPRACH_target(1) are different values from each other, and PPRACH_target(0) > PPRACH_target(1). Thus, for example, in a 2-way random access procedure, the terminal 200 can easily configure a higher transmit power for the PRACH preamble to improve the received power at the base station 100. On the other hand, for example, in a 4-way random access procedure, the terminal 200 can avoid configuring an unnecessarily high transmit power for the PRACH preamble.

[0192] Option 1 allows configuring proper received power targets for PRACH preambles for the 2-round random access procedure and the 4-round random access procedure, respectively.

[0193] <Option 2>

In option 2, a parameter representing the number of PRACH preamble transmission symbols (or PRACH preamble length) is added to the target received power value for the PRACH preamble to calculate the transmit power.

[0194] For example, the transmit power for the PRACH preamble is calculated as follows:

P _PRACH = min{P _CMAX , P _{PRACH_target} + β + PL} … (equation 7).

[0195] Here, β is a coefficient representing the number of PRACH preamble transmission symbols. For example, β = 0 may be configured when the number of PRACH preamble transmission symbols is 1 slot (14 symbols), and β = 3 may be configured when the number of PRACH preamble transmission symbols is 0.5 slots (7 symbols). It should be noted that the value of β is not limited to these values.

[0196] In Embodiment 2, even when the respective RACH formats with different symbol lengths differing between procedures are used in the 2-round random access procedure and the 4-round access procedure, a proper received power target value can be configured for each of the RACH formats.

[0197] Option 1 and Option 2 have been described above.

[0198] It should be noted that option 1 and option 2 can be combined. In addition, terminal 200 may select one of the 2-round random access procedure and the 4-round random access procedure by applying at least one of implementations 1 to 4 after calculating the transmit power for the PRACH preamble based on the methods described herein. .

[0199] In addition, herein, a case has been described as one example in which the transmission power for the PRACH preamble in the 2-round random access procedure is set higher than the transmission power for the PRACH preamble in the 4-round random access procedure. However, the present invention is not limited to this, and the transmission power for the PRACH preamble in the 4-way random access procedure can be set higher than the transmission power for the PRACH preamble in the 2-way random access procedure.

[0200] (Embodiment 6)

In Embodiments 1-5 described above, a configuration is assumed in which the PRACH and PUSCH preamble are time division multiplexed (TDM) in message A, for example, as shown in FIG. 11. However, in message A, the multiplexing is not limited to time division multiplexing, and the PRACH and PUSCH preamble may be frequency division multiplexed (FDM), for example, as shown in FIG. 12.

[0201] In the case of FDM, the terminal calculates the sum of the PRACH preamble transmit power value and the PUSCH transmit power value (in other words, the total transmit power) based on the PRACH preamble transmit power value and the PUSCH transmit power value. Then, the terminal compares the calculated total transmit power with the maximum transmit power that the terminal can transmit, and when the total transmit power is greater than the maximum transmit power, the terminal performs power scaling.

[0202] However, when the transmit powers for both the PRACH preamble and the PUSCH are scaled the same, it may happen that none of the power values will satisfy the allowable values (for example, the transmit powers that allow the base station to receive the PRACH and PUSCH preamble signals with sufficient reliability).

[0203] In this regard, the present embodiment will be described in connection with the operation performed by the terminal when the sum (total transmission power) of the PRACH preamble transmission power value and the PUSCH transmission power value is greater than the maximum power.

[0204] It should be noted that since the base station and the terminal according to the present embodiment have the same basic configurations as the base station 100 and the terminal 200 according to Embodiment 1, they will be described with reference to FIG. 4 and 5.

[0205] <Option 1>

In Case 1, when the total transmit power is greater than the maximum transmit power, the terminal 200 returns to the 4-way random access procedure.

[0206] For example, when the total transmit power is greater than the maximum transmit power, the terminal 200 during transmission of message A transmits the PRACH preamble without transmitting the PUSCH.

[0207] Accordingly, even when the calculated total transmission power is greater than the maximum transmission power, unnecessary collisions due to PUSCH can be reduced by the terminal 200 for which the transmission quality cannot satisfy the given reliability.

[0208] <Option 2>

In option 2, terminal 200 scales the transmit power for PUSCH when the total transmit power is greater than the maximum transmit power. In other words, terminal 200 does not scale the transmit power for the PRACH preamble.

[0209] It should be noted that in the PUSCH transmission power scaling method, the TBS for transmitting the PUSCH message A need not be fixed. For example, terminal 200 may select one TBS from a plurality of TBSs based on the UP data (eg, amount of user plane data) actually transmitted by terminal 200.

[0210] In this case, the terminal 200 calculates, for example, the sum (total transmit power) of the PRACH preamble transmit power and the PUSCH transmit power, and compares the calculated transmit power with the maximum transmit power with which the terminal can transmit. When the total transmit power is greater than the maximum transmit power, terminal 200 may scale the TBS (eg, select a smaller TBS) PUSCH. Then, terminal 200 may recalculate the transmit power for the PUSCH for which the TBS is scaled, and may transmit the PRACH and PUSCH preamble using the scaled TBS in message A when the calculated transmit power satisfies the allowable value. This method allows the terminal 200 to transmit a reliable PUSCH for as long as possible to reduce the delay caused by returning to the 4-round random access procedure. It should be noted that when the TBS cannot be scaled (a smaller TBS cannot be selected), the terminal 200 may transmit the PRACH preamble without transmitting the PUSCH during message A transmission (in other words, return to the 4-round random access procedure).

[0211] It is understood that, according to the present embodiment, the terminal 200 selects a 2-round random access procedure (in other words, PRACH and PUSCH preamble transmission) or a 4-round random access procedure (in other words, PRACH preamble transmission without PUSCH transmission) in depending on the channel state between the base station 100 and the terminal 200. For example, when the channel state is bad and the transmission quality does not satisfy the predetermined reliability, the terminal 200 selects the 4-way random access procedure and does not transmit the PUSCH. Thus, PUSCH collisions with other terminals can be reduced.

[0212] Embodiments of the present invention have been described above.

[0213] (Other implementations)

(1) Examples of the timing in which the terminal 200 selects one of the 2-way random access procedure and the 4-way random access procedure include the following timings.

[0214] <Option 1>

The terminal 200 may select one of the 2-way random access procedure and the 4-way random access procedure in all timings 1-3 described above. In addition, the selection method for selecting the random access procedure for the above-described timings 1-3 may be different.

[0215] <Option 2>

The terminal 200 may select one of the 2-way random access procedure and the 4-way random access procedure at a particular timing from among the timings 1-3 described above. For example, there may be one specific timing or multiple specific timings. In addition, the selection method for selecting the random access procedure for the above-described timings 1-3 may be different.

[0216] (2) For example, the following method can be used as a method for configuring a parameter for calculating transmission powers when returning from a 2-round random access procedure to a 4-round random access procedure.

[0217] <Option 1>

The terminal 200 constantly uses the parameter for the 2-way random access procedure in the 4-way random access procedure.

[0218] <Option 2>

For the 4-way random access procedure, terminal 200 uses a parameter.

[0219] In addition, the transmission power control parameters for the 2-way random access procedure and the transmission power control parameters for the 4-way random access procedure can be configured independently of each other. For example, the transmit power control parameters include the PRACH_target received power target value _{PRACH_target} for the PRACH preamble, the offset value for PUSCH relative to the received power target value for the PRACH preamble, the maximum transmit power at which terminal 200 can transmit, a weighting factor α representing the degree of loss compensation in bandwidth, etc.

[0220] (3) The present invention may be implemented by software, hardware, or software in cooperation with hardware. Each functional block used in the description of each embodiment set forth above may be partially or wholly implemented by an LSI such as an integrated circuit, and each process described in each embodiment may be controlled in part or wholly by the same LSI or combination. BIS. The LSI may be formed separately as chips, or a single chip may be formed to include some or all of the functional blocks. The LSI may include input and output data associated with it. The LSI in this document may be referred to as an integrated circuit (IC), system LSI, super-LSI or ultra-LSI depending on the difference in the degree of integration. However, the implementation method of the integrated circuit is not limited to the LSI, and may be implemented using a dedicated circuit, a general purpose processor, or a special purpose processor. In addition, an FPGA (Field Programmable Gate Array) can be used, which can be programmed after the LSI is manufactured or reconfigurable processor, in which the connection configuration and settings of the circuit cells located inside the LSI can be changed. The present invention may be implemented as digital data processing or analog data processing. If future integrated circuit technology replaces LSIs as a result of the development of semiconductor technology or other derivative technology, functional blocks can be integrated using future integrated circuit technology. In addition, biotechnology may be applied.

[0221] The present invention can be implemented by any kind of device, device or system having a communication function, which are called communication devices. The communication device may include a transceiver and a processing/control circuit. The transceiver may comprise a receiver and a transmitter and/or function as both a receiver and a transmitter. A transceiver in the form of a transmitter and receiver may include a radio frequency (RF) module and one or more antennas. The RF module may include an amplifier, an RF modulator/demodulator, and the like. Non-limiting examples of such communication devices include a telephone (such as a cell phone), a tablet, a personal computer (PC) (such , desktop computer, netbook), camera (e.g. digital camera/camcorder), digital player (digital audio/video player), wearable device (e.g. wearable camera, smart watch, tracker), game console, digital e-reader books, a device for health/medical teleservices (remote health and medical services), and a vehicle providing communication functionality (eg, a car, an airplane, a ship), as well as various combinations thereof.

[0222] The communication device is not limited to portable or mobile devices, and may also include any kind of device, device, or system that is non-portable or stationary, such as a smart home device (e.g., household appliance, lighting, smart meter, control panel), a vending machine and any other “things” in the Internet of Things (IoT) network.

[0223] Communication may include data exchange, for example, via a cellular system, a wireless LAN system, a satellite system, etc., and various combinations thereof.

[0224] The communication device may include a device, such as a controller or sensor, that is connected to the communication device that performs the communication function described in the present invention. For example, the communication device may include a controller or sensor that generates control signals or data signals used by the communication device to perform the communication function of the communication device.

[0225] Communication devices may also include an infrastructure facility such as a base station, access point, and any other device, device, or system that communicates with or controls devices, such as the devices in the non-limiting examples above.

[0226] A terminal according to an embodiment of the present invention includes: a control circuit configured to select one of a first method and a second method based on channel quality, the first method for transmitting a random access signal including a preamble section and a data section , the second method is for transmitting a random access signal including a preamble section but not including a data section; and a transmission circuit configured to transmit the random access signal based on the selected method.

[0227] In the exemplary embodiment of the present invention, the channel quality is a transmit power for a random access signal, and the control circuit selects the first method when the transmit power is greater than or equal to the threshold, or selects the second method when the transmit power is less than the threshold. values.

[0228] In an exemplary embodiment of the present invention, the channel quality is the reception quality of the downlink signal.

[0229] In an exemplary embodiment of the present invention, a random access signal resource is associated with each of the plurality of downlink signals, and in the first method, the transmission circuit transmits the random access signal using the resource associated with the signal of the plurality of downlink signals to which the reception quality is greater than the first threshold or equal to the first threshold, or when there is no signal among the downlink signals for which the reception quality is greater than the first threshold or equal to the first threshold, the transmission circuit transmits the random access signal based on the second method.

[0230] In the exemplary embodiment of the present invention, in the second method, the transmission circuit transmits a random access signal using a resource associated with a signal of a plurality of downlink signals for which the reception quality is greater than or equal to the second threshold, or transmits the signal random access based on a resource associated with any one of the plurality of downlink signals, when among the plurality of downlink signals there is no signal for which the reception quality is greater than or equal to the second threshold, and the first threshold is different from the second threshold .

[0231] In the exemplary embodiment of the present invention, the channel quality is the transmission power for the data partition, and the control circuit reduces the size of the data partition when the transmission power is less than a threshold, and the transmission circuit transmits a random access signal based on the first method when the power transmission after reducing this size is greater than the threshold value or equal to the threshold value.

[0232] In an exemplary embodiment of the present invention, when it is desired to retransmit the random access signal, the control circuit increases the transmit power for the data section compared to the transmit power during the previous transmission without changing the transmit power for the preamble section compared to the transmit power during the time of the previous transmission.

[0233] In the exemplary embodiment of the present invention, the channel quality is the transmission power for the data partition, and the transmission scheme transmits a random access signal based on the first method, when the increased transmission power for the data partition is greater than or equal to the threshold, or transmits a random access signal based on the second method when the increased transmit power for the data partition is less than a threshold.

[0234] In the exemplary embodiment of the present invention, the amount of increase in transmission power differs between the first method and the second method.

[0235] In the exemplary embodiment of the present invention, when the random access signal is to be retransmitted based on the second method after the random access signal has been transmitted based on the first method, the control circuit configures the transmission power increased in the first method as transmit power for the random access signal in the second method.

[0236] In the exemplary embodiment of the present invention, when, when it is necessary to retransmit the random access signal, control information including a parameter related to transmission power control is indicated by the base station, the transmission scheme transmits the random access signal based on this parameter, which is based on the first method.

[0237] In the exemplary embodiment of the present invention, the control information also includes information indicating one of the first method and the second method, and the control circuit selects one of the first method and the second method based on the control information.

[0238] In the exemplary embodiment of the present invention, when the random access signal needs to be retransmitted, the control circuit increases the first transmission power for the preamble section and the second transmission power for the data section.

[0239] In the exemplary embodiment of the present invention, the channel quality information is the first transmit power and the second transmit power, and the control circuit selects the first method when both of the first transmit power and the second transmit power are greater than or equal to the threshold, or selects the second method when at least one of the first transmit power and the second transmit power is less than a threshold value.

[0240] In the exemplary embodiment of the present invention, the amount of increase in transmission power differs between the first method and the second method.

[0241] In the exemplary embodiment of the present invention, when the random access signal is to be retransmitted based on the second method after the random access signal has been transmitted based on the first method, the control circuit configures the transmission power increased in the first method as transmit power for the random access signal in the second method.

[0242] In an exemplary embodiment of the present invention, the control circuit selects the second method when the number of random access signal retransmissions based on the first method exceeds the upper limit.

[0243] The transmission method according to an exemplary embodiment of the present invention includes: selecting one of the first method and the second method based on channel quality, the first method is for transmitting a random access signal including a preamble section and a data section, the second method is for transmitting a random access signal including a preamble section but not including a data section; and transmitting the random access signal based on the selected method.

[0244] Japanese Patent Application Disclosure No. 2019-061490 dated March 27, 2019, including the technical description, drawings, and abstract, is incorporated herein by reference in its entirety.

Industrial Applicability

[0245] An exemplary embodiment of the present invention is useful for mobile communication systems.

List of reference positions

[0246]

100 - base station

101, 209 - controller

102 - data generator

103, 106, 109, 211, 213 - encoder

104, 107, 110, 212, 214 - modulator

105 - senior control signal generator

108 - downlink control signal generator

111, 215 - signal distributor

112, 216 - IFFT section

113, 217 - transmitter

114, 201 - antenna

115, 202 - receiver

116, 203 - FFT section

117, 204 - highlighter

118 - detector

119, 205 - demodulator

120, 206, 208 - decoder

200 - terminal

207 - downlink control signal demodulator

210 - PRACH preamble generator

Claims (73)

1. Communication terminal, containing: a control circuit configured to select one of the first method and the second method based on channel quality, the first method is for transmitting a random access signal including a preamble section and a data section, the second method is for transmitting a random access signal including a preamble section, but not including a data section; and a transmission scheme configured to transmit the random access signal based on the selected method, wherein each of the plurality of downlink signals has a random access signal resource associated with it, characterized in that in the first method, the transmission circuit is configured to transmit a random access signal using a resource associated with a signal from a plurality of downlink signals for which the reception quality is greater than or equal to the first threshold, in the second method, the transmission circuit is configured to transmit a random access signal using a resource associated with a signal from a plurality of downlink signals for which the reception quality is greater than the second threshold value or equal to the second threshold value, the first threshold is different from the second threshold. 2. The communication terminal according to claim 1, wherein the control circuit selects the first method when the channel quality is greater than the first threshold, or selects the second method when the channel quality is less than the first threshold or equal to the first threshold. 3. The communication terminal according to claim 2, wherein the channel quality is the reception quality of the downlink signal. 4. The communication terminal according to claim 1, in which, for transmitting the random access signal, the control circuit selects a resource associated with the power of the received synchronization reference signal (Synchronization Signal Reference Signal Received Power, SS-RSRP), which exceeds the second threshold value, when there is at least one resource associated with the SS-RSRP that exceeds the second threshold, the second threshold being different between the first method and the second method. 5. The communication terminal according to claim 1, wherein the control circuit selects the first method from the first method and the second method when initially transmitting message A over the first method. 6. The communication terminal of claim 1, further comprising a receiving circuit that receives a message B that is a response to the transmission of message A by the first method, wherein the control circuit concludes that the random access procedure of the first method has been successfully completed when the message demodulation process is successfully completed. B, including identification information on the communication terminal. 7. The communication terminal according to claim 1, further comprising a receiving circuit that receives a message B that is a response to the transmission of message A according to the first method, and in response to receiving message B, including a request for retransmission, the transmission circuit performs a retransmission transmission of a data section without a preamble section. 8. The communication terminal of claim 7, wherein message B includes uplink resource information, and the transmission scheme retransmits the data section using the uplink resource information. 9. The communication terminal according to claim 1, wherein, in response to the transmission of message A by the first method, when message B, which is a response to the transmission of message A, is not received within a predetermined period, the transmission circuit performs retransmission of message A by the first method. 10. The communication terminal according to claim 1, wherein the random access signal transmission is performed using power ramping, wherein the power ramping step is different between the first method and the second method. 11. The communication terminal according to claim 1, wherein when the random access procedure is not completed after the limit number of transmissions of message A in the first method, the control scheme is switched to the second method. 12. The communication terminal according to claim 1, wherein the target received power value for the preamble section is configured independently for the first method and the second method, respectively. 13. Method of communication, including: selecting one of the first method and the second method based on the channel quality, wherein the first method is for transmitting a random access signal including a preamble section and a data section, the second method is for transmitting a random access signal including a preamble section but not including a data section; and transmitting the random access signal based on the selected method, wherein each of the plurality of downlink signals has a random access signal resource associated with it, characterized in that in the first method, the transmission circuit is configured to transmit a random access signal using a resource associated with a signal from a plurality of downlink signals for which the reception quality is greater than or equal to the first threshold, in the second method, the transmission circuit is configured to transmit a random access signal using a resource associated with a signal from a plurality of downlink signals for which the reception quality is greater than the second threshold value or equal to the second threshold value, the first threshold is different from the second threshold. 14. Base station, containing: a receiving scheme that receives from the communication terminal a random access signal based on one of the first method and the second method selected based on the channel quality, the first method is for transmitting by the communication terminal a random access signal including a preamble section and a data section, the second method is for the communication terminal to transmit a random access signal including a preamble section but not including a data section; and a transmission scheme that transmits a response to the random access signal based on one of the first method and the second method selected in the communication terminal, wherein each of the plurality of downlink signals has a random access signal resource associated with it, characterized in that in the first method, the transmission circuit is configured to transmit a random access signal using a resource associated with a signal from a plurality of downlink signals for which the reception quality is greater than or equal to the first threshold, in the second method, the transmission circuit is configured to transmit a random access signal using a resource associated with a signal from a plurality of downlink signals for which the reception quality is greater than the second threshold value or equal to the second threshold value, the first threshold is different from the second threshold. 15. The base station of claim 14, wherein the communication terminal selects the first method when the channel quality is greater than the first threshold, or the communication terminal selects the second method when the channel quality is less than the first threshold or equal to the first threshold. 16. The base station of claim 15, wherein the channel quality is the reception quality of the downlink signal at the communication terminal. 17. The base station according to claim 14, wherein, in order to receive the random access signal, the receiving circuit receives the random access signal on a resource associated with a power of the received synchronization reference signal (Synchronization Signal Reference Signal Received Power, SS-RSRP) that exceeds the second threshold. when there is at least one resource associated with the SS-RSRP that exceeds the second threshold, the second threshold being different between the first method and the second method. 18. The base station according to claim 14, in which the first method is selected from the first method and the second method at the initial transmission of message A by the first method. 19. The base station according to claim 14, wherein the transmission scheme transmits message B, which is a response to receiving message A by the first method, the message B including identification information at the communication terminal is used to determine whether the procedure is successfully completed. random access of the first method. 20. The base station of claim 14, wherein the transmission scheme transmits message B, which is a response to receiving message A by the first method, wherein in response to transmission of message B including a retransmission request, the receiving scheme receives a retransmission of a section data without a preamble section. 21. The base station according to claim 20, in which message B includes uplink resource information, and the receiving scheme receives the retransmission of the data section on the resource indicated by the uplink resource information. 22. The base station of claim 14, wherein, in response to receiving message A in the first method, when message B in response to receiving message A is not transmitted within a predetermined period, the receiving circuit receives retransmission of message A in the first method. 23. The base station of claim 14, wherein the power ramp step used for transmitting the random access signal is configured differently for the first method and the second method. 24. The base station of claim 14, wherein when the random access procedure is not completed after the limit number of transmissions of message A in the first method, the receiving circuit receives the random access signal in the second method. 25. The base station of claim 14, wherein the received power target value for the preamble section is configured independently for the first method and the second method, respectively. 26. Communication method, including: receiving from the communication terminal a random access signal based on one of the first method and the second method based on channel quality, wherein the first method is for the communication terminal to transmit a random access signal including a preamble section and a data section, the second method is for the communication terminal to transmit a random access signal an access including a preamble section but not including a data section; and transmitting a response to the random access signal based on one of the first method and the second method selected in the communication terminal, wherein each of the plurality of downlink signals has a random access signal resource associated with it, characterized in that in the first method, the transmission circuit is configured to transmit a random access signal using a resource associated with a signal from a plurality of downlink signals for which the reception quality is greater than or equal to the first threshold, in the second method, the transmission circuit is configured to transmit a random access signal using a resource associated with a signal from a plurality of downlink signals for which the reception quality is greater than the second threshold value or equal to the second threshold value, the first threshold is different from the second threshold. 27. An integrated circuit containing: a generation circuit that controls the selection of one of the first method and the second method based on channel quality, the first method is for transmitting a random access signal including a preamble section and a data section, the second method is for transmitting a random access signal including a preamble section , but not including the data section; and a transmission scheme that controls transmission of the random access signal based on the selected method, wherein each of the plurality of downlink signals has a random access signal resource associated with it, characterized in that in the first method, the transmission circuit is configured to transmit a random access signal using a resource associated with a signal from a plurality of downlink signals for which the reception quality is greater than or equal to the first threshold, in the second method, the transmission circuit is configured to transmit a random access signal using a resource associated with a signal from a plurality of downlink signals for which the reception quality is greater than the second threshold value or equal to the second threshold value, the first threshold is different from the second threshold. 28. An integrated circuit containing: a reception scheme that controls the reception of a random access signal transmitted from a communication terminal based on one of the first method and the second method based on channel quality, the first method being for transmitting by the communication terminal a random access signal including a preamble section and a data section, wherein the second method is for the communication terminal to transmit a random access signal including a preamble section but not including a data section; and a transmission scheme that controls the transmission of a response to the random access signal based on one of the first method and the second method selected in the communication terminal, wherein each of the plurality of downlink signals has a random access signal resource associated with it, characterized in that in the first method, the transmission circuit is configured to transmit a random access signal using a resource associated with a signal from a plurality of downlink signals for which the reception quality is greater than or equal to the first threshold, in the second method, the transmission circuit is configured to transmit a random access signal using a resource associated with a signal from a plurality of downlink signals for which the reception quality is greater than the second threshold value or equal to the second threshold value, the first threshold is different from the second threshold.

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